Conference to Consider the Establishment of Water Quality Standards for the Mississippi River Basin Interstate Waters--State of Iowa (2nd : 1969 : Davenport, Iowa)
Progress Evaluation Meeting in the Matter of Pollution of the Interstate and Intrastate Waters of the Upper Mississippi River and Its Tributaries: Minnesota and Wisconsin (1968 : Minneapolis, Minn.)
Conference in the Matter of Pollution of the Interstate and Intrastate Waters of the Upper Mississippi River and Its Tributaries--Minnesota and Wisconsin (2nd : 1967 : Minneapolis)